Synthesis and characterization of organotin-substituted heteropoly tungstosilicates and their biological activity I

Tris(organotin)-substituted alpha,beta-Keggin heteropoly-tungstosilicates alpha-[(RSn)(3)SiW9O37](7-), alpha-[(RSn)(3)(SiW9O34)(2)](11-), beta-[(RSn)(3)SiW9O37](7-) and beta-[(RSn)(3)(SiW9O34)(2)](11-) have been prepared by reaction of the beta-methoxycarbonylethyltin, beta-methoxycarbonyl(i)-propyltin, cyanoethyltin trichlorides with trivacant precursors alpha,beta-SiW9O3410- respectively. The products were characterized by elemental analysis, IR, electrochemistry, H-1, Sn-119, and W-183 NMR spectroscopy. W-183 NMR spectra of the compounds consist of two lines with the intensity ratio 2:1 or 1:2, and demonstrated that alpha,beta-[(RSn)(3)(SiW9O37)](7-) have the Keggin structure and alpha,beta-[(RSn)(3)(SiW9O34)(2)](11-) have a sandwich structure. The title complexes display antitumoral activity in vitro. (C) 1999 Elsevier Science Ltd. All rights reserved.